Magnetic cores of coil components for use in the high frequency range have been required to have a high magnetic permeability and low-loss characteristics in the high frequency range. One example of such magnetic cores is a dust core obtained by compression molding of magnetic metal powder (for example, such a core is disclosed in Japanese Unexamined Patent Application Publication No. 2003-217919).
With the increasing use of Near Field Communication (NFC) and wireless power transmission in recent years, there have been an increasing number of circuits that use larger AC currents than before. Among such wireless power transmission circuits, a magnetic resonance circuit is able to feed power to a plurality of devices and thus is being considered for use for mobile terminals such as smartphones. Since the magnetic resonance circuit is designed to operate at a resonant frequency of about 6.78 MHz, for the circuit to output high power at that frequency, a coil component is needed whose Q factor does not decrease much even when a large amplitude current is passed.